天津东南部某区域不同土地利用方式下土壤重金属的累积特征

Accumulation Characteristics of Heavy Metals in Soils as Affected by Land Use in Southeast Tianjin

为分析天津东南部某区域不同土地利用方式下土壤中重金属(As、Cd、Cr、Co、Cu、Pb、Ni、V、Zn、Hg)的累积程度,在该研究区工业用地、居住用地和农业用地3种土地利用方式下的土壤表层采集样品进行重金属含量分析,并运用单因子指数法和内梅罗综合指数法对重金属累积状况进行评价。结果显示,在工业用地土壤中累积程度较高的重金属为Cd、As、Co、Ni和Zn,在居住用地中为Cd、As、Co、Zn和Pb,而农业用地土壤为Cd、As、Co和Zn。研究区土壤重金属状况总体表现为Cd为重度累积,As为中度累积,Co、Cu、Pb、Ni、V和Zn为轻度累积,Cr和Hg基本处于背景值水平。土壤重金属内梅罗综合指数评价结果表明,研究区大部分地区的土壤重金属累积程度都达到中度及以上水平,内梅罗综合指数平均值由高到低依次为农业用地、工业用地和居住用地。与国内其他地区相比,该研究区Cd、As和Co累积程度明显偏高。

In order to investigate accumulation of heavy metals（ As,Cd,Cr,Co,Cu,Pb,Ni,V,Zn,Hg） in topsoils different in land use in Southeast Tianjin,soil samples were collected from places different in land use,i. e. industrial land,residential land and agricultural land,for analysis of contents of the heavy metals in the topsoils. Accumulations of the heavy metals were characterized with the single factor index method and the Nemerow comprehensive index method.Results show that industrial lands were quite high in accumulation of Cd,As,Co,Ni and Zn; residential lands were in accumulation of Cd,As,Co,Zn and Pb; and agricultural lands were in accumulation of Cd,As,Co and Zn. In the studied area as a whole,Cd was heavily accumulated,As moderately accumulated,and Co,Cu,Pb,Ni,V and Zn slightly accumulated; and Cr and Hg were quite close to their respective background value. The evaluation using the Nemerow comprehensive index method indicated that the heavy metals in the soils of most parts of the studied area accumulated to a moderate or severe degree,and by means of the evaluation using the Nemerow comprehensive index method,the three types of land use displayed an order of agricultural land industrial land residential land. Comparing with other regions of China,the studied area was obviously higher in accumulation of Cd,As and Co in surface soil.